Derek Jeter has struggled in his final season. / John E. Sokolowski, USA TODAY Sports

by Jorge L. Ortiz, USA TODAY Sports

by Jorge L. Ortiz, USA TODAY Sports

TORONTO -- Derek Jeter's well-known aversion to public introspection gets heightened at the mention of his 40th birthday, a milestone he reaches today.

His protective shield goes up, and Jeter refuses to entertain the notion of making any allowances to Father Time, saying things like, "It's like 39, 38, 37. They're all the same to me."

Except he's not the same.

At 37, the New York Yankees shortstop reached his 3,000th hit and batted .297, and at 38 he led the American League with 216 hits while putting up a .316 batting average, spitting in the face of countless forecasts of his decline.

Now the wind is blowing in the opposite direction, and even an iconic player with legendary resolve can't change that.

The aftereffects of a broken ankle suffered during the 2012 playoffs cost Jeter nearly all of last season, and while he has bounced back to play in 67 of the Yankees' 77 games, he hasn't returned to the level of 2012, and it's unrealistic to expect he will.

Entering Wednesday's game, Jeter was hitting .267 with a slugging percentage of .327, which would rank as the lowest figures of his career in any full season. Only 11 of his 71 hits had gone for extra bases. His on-base-plus-slugging percentage of .649 ranked 19th among major league shortstops.

Jeter's fielding, long derided by those who rely on advanced metrics, remains subpar. His "ultimate zone rating" of minus 2 was 18th in the majors, and his "defensive runs saved" of minus 4 ranked 21st.

Those are all indications that Jeter's final season might wind up falling somewhere between Willie Mays' lamentable farewell and Mariano Rivera's good-as-ever exit, likely closer to the first.

Jeter says he simply doesn't think about age, acknowledging only that his comeback hasn't gone the way he figured.

"It's taken awhile to get back into the swing of things," Jeter said. "You play this game every day for a reason. When you miss an entire year, it takes a little while to get back into the flow of the game. I thought it would come quicker."

Even the mental acuity that separated Jeter from so many of his peers - his out-of-nowhere flip to get an out at home plate and turn around the 2001 division series stands as one of the headiest plays ever - might not be quite the same.

Jeter made mental blunders on back-to-back plays in the fifth inning Tuesday, costing the Yankees three runs in a 7-6 loss to the Toronto Blue Jays.

With runners on first and second and two outs, Jeter failed to take into account that speedy Jose Reyes would have a great jump running toward second as Mark Teixeira played well off first base against right-handed-hitting slugger Edwin Encarnacion. When Encarnacion hit a routine chopper to short, Jeter looked to second and then third before throwing too late to first.

On the next pitch, Colby Rasmus ripped a liner to the wall in right and was caught in a rundown between second and first. Jeter tried to run him back by himself, but Rasmus beat him to the bag and Encarnacion took advantage to scramble home with the Jays' sixth run of the game.

"I should have known Tex was playing more over in the hole and Reyes had a huge lead, and I couldn't get him at second," Jeter said.

The Yankees realize Jeter no longer makes plays other shortstops do. They have one of those in their ranks, Brendan Ryan, who regularly ranks among the top defensive shortstops in the game. But Ryan is a career .238 hitter, and that's a luxury they can't afford, not with an offense that has produced the fourth-fewest runs in the league this year.

Plus, this is supposed to be a season to celebrate Jeter's numerous accomplishments as one of the greatest Yankees, the franchise's all-time leader in hits (3,387) and team victories (1,588), as well as the active player with the highest personal winning percentage (.596).

Those last two figures are the ones Jeter cares most about, a mind-set he has instilled on two decades' worth of teammates.

Alfonso Soriano, an outfielder in his second stint with the Yankees but initially Jeter's double-play partner when Soriano came up for good in 2001, said that's the first thing he thinks of when he recalls Jeter in his heyday.

"The way he played, with a lot of energy and only one thing in his mind, which was to win regardless of whether he had a good or bad day," Soriano said. "The main thing was getting the win."

That unyielding commitment to winning is one of the reasons Jeter commands such admiration in the game. And even as his skills fade, his legacy and ability to endure baseball's daily grind at his position earn him extra respect.

In the last half-century, the only shortstops to play every day at 40 were Hall of Famer Barry Larkin and Omar Vizquel.

"Do you know how difficult it is to play shortstop? It's super hard," said Reyes, a four-time All-Star shortstop. "You have to be in on all the plays. And to be moving so much at 40? Wow, Jeter, many blessings. My respect to you."